Assigitob



Oct. 8, 191 9 v, LANDON 1,730,853

VARIABLE CONDENSER Filed May 27, 1926 INVENTOR Vernon D. Landon WITNESSES:

Patented Get. 8, 1929 parts VERNON D. LANDON, OF EAST PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO \VESTING- HOUSE ELECTRIC, z IvILLNUFACTUBING CQHPAHY, A CORPORATION OF PENNSYL- vANrA VARIABLE coivDsNsEB Application filed Ma e'z, 192e."seria1 No. 111,928.

My invention relates to variable condensers audit has particular relation to Vernier adjustments for such condensers, in which a verysmall change in capacity is caused by a comparatively large motion of the operating means; Y

one object of my invention is to provide a variable condenser! that may be fixed in ads j usted position.

Another object of my invention is to provide a variable condenser that may be roughly adjusted to a predetermined frequency and that maybe further adjusted by an independent vern ier movement.

Another object of my invention isto provide a variable condenser that will remain in a djust-ed position, irrespective of shocks and jarring. v

' A still furtherobjectofmy invention is to provide a variable condenser with a vernier movement that is effective only over a preselected frequency range.

' Variable condensers designed for use on aeroplanes, and in other situations where they will be subjected to frequent shocks and jars, must be equipped with means for fixing the relative position of the plates firmly after adjustment.

I am aware-that, in the prior art, variable condensers have been provided with a variety of adjustment-holding devices, such as setscrews, pins and the like. In so far 2151 am aware, however, none of these condensers have been provided with slow-motion means for permitting a limited movement in each of the fixed posit-ions. Such a condenser is extremely desirable in order that the tuning of the receiving circuit may be readily adjustable to compensate for slight frequencyshifts of the incoming signal.

My invention provides a condenser that may be locked in any one of a plurality of predetermined positions and, at the same time, may be varied slightly in capacity, either above or below the capacity corresponding to any locked position. Specially, my condenser embodies a device for locking the rotor plates in a definite position, and comprises a dial-actuated cam for giving a slight angular movement to both the locked r'otorand' theloeking means considered as a preferred form of my invention,'as applied to the usual typeof rotary variable condenser.

' A variable condenser has a stator sect-ion comprising two end plates 1 and 2 mounted on a base 3, between which are held, in spaced relation, a plurality of stator plates 4, Interleaved' between the stator plates 4 are a plurality of rotor plates 5, afiixed to fa shaft 6 which is mounted 'forpartial rotation in bearings carried by the end plates 1 and '2. A sector 7, having saw-tooth indentations 8 on an edge thereof','is also affixed to the shaft 6, and held firmly against rotative movement thereon. I mounted on the end of the shaft- 6 and is held in placethereon by a washer 10 and a set-screw'll. The movable member 9 has pivotally mounted thereon an arm'12 carrying a detent 13, which is pressed into engagement with the sector 7 by means of a spring 14, the latter being affixed to the movable member 9.

' A cam 15, keyed or otherwise fastened, to a shaft 16 mounted in a bearing 17 carried by the end plate1, is so arranged that it bears against the under surface of the movable member 9. In order that the movable member may be held firmly in contact with the cam 15, a coil spring 18 is provided, one end of which is held by means of a fastening, device 19 mounted on the base 3, and the other end of which is arranged to pass through an opening in the lower end of a pin 20 carrie by the member 9.

The shaft, upon which is mounted the cam 15, also carries an operating knob 21, en abling it to be rotated for a purpose which will be later explained.

In the operation of a variable condenser made according to my invention, the rotor, carrying the notched sector 7, is adjusted to a predetermined position and there locked by the inter-action of the serrations 8 and the detent 13. Fine adjustment is now obtained A movable member '9 is loosely by rotation of the shaft 16 carrying the cam 15, which moves the rotor assen'ibly and the locking means, as a whole, a slight amount with relation to the stator. The notches are. preferably so chosen that they will correspond to the principal frequencies it is desired to receive, and the cam surface is designed to give a variation of approximately thirty kilocycles on each side of the tuning determined by the notches.

My invention is not to be restricted, however, to use in connection with a variable condenser of the rotary type, being equally adaptable, with but slightinodification, to all of the various kinds of variable condensers known to the art. In short, my invention provides a condenser which may be roughly adjusted and locked in position, and then given a final fine adjustment, the fine-adjusting means being self locking.

The advantages of my invention are ob vious to those skilled in the. art. W'hen used in receiving or transn'iitting sets for aeroplanes, the eonstant vibration of which would quickly throw the usual variable condenser out of adjustment, my condenser has proved of great value. Tuning to a desired signal is quickly and easily accomplished, as the sector serrations may be either marked to correspond to definite stations or to the frequency for which the set is tuned when the detent is in the serration.

Although I have shown and described a specific embodiment of my invention, I am aware that many modifications will suggest themselves to those skilled in the art. My invention is not to be limited, therefore, except in so far as is necessitated by the prior art, or as indicated by the appended claims.

I claim as my invention:

1. In a condenser, a stationary element. a movable element. a member movable with said movable element. a second member movably mounted on said fixed element, and means for; locking the two members together, whereby said members may be simultaneously moved.

2. In a condenser, a stationary element. a movable element, interlocking means for holding the elements in a predetermined space relation. and additional means for slightly varying said space relation without disturbing the adjustment of the holding means. the elements constituting said interlocking means being relatively movable with respect to each other.

3. In a condenser, a stationary element, a movable element, means comprising cooperating locking members for holding the elements in a semi-fixed relation, and additional means for moving said locking means to thus vary the semi-fixed relation without disturbing the cooperation of the locking members.

4;. In a condenser, a stationary element, a movable element, locking means for predetcrmining a plurality of semi-fixed space relations thcrehctwecn, and continuously operable means associated with said locking ine-ans for cyclically varying the space relation determine-fl by the locking means.

5. In a variable condenser, a stationary element, a movable element, locking means for holding the elements in a semi-fixed capacity relationship, and continuously operable means, including a cam, for moving said looking means to afford vernier adjustment of the capacity.

6. In a. condenser, a stationary element. a movable clement, releasable means for bolding the elements in semi-fixed relation, and continuously operable means, includim a cam, for moving said locking means to a rd vernicr adjustment.

7. In a condenser, a stationary element, a movable element, mutually engageable locking means carried partially by the movable element and partially by the stationary element for n'iaintaining the elements in a semilixed relation. and additional means carried by the stationary element for moving the. locking means to provide for Vernier adjustincnl.

8. In a condenser, a stationary element, a shaft. a movable element mounted on said shaft. a serrated sector carried by said shaft, a arm loosely mounted on the shaft and carrying a detent arranged to cooperate with the sector. means for maintaining the arm in semi-ti. ;ed relation to the stationary element, and means, including a cam, for slightly varying the position of the arm with reference to the stationary element.

9. In a condenser, a stator, a rotor, locking means therefor comprising an element carried by the rotor and an element carried by the stator, and additional means whereby both elements of the locking means may be moved relative to the stator.

10. In an adjustable condenser, means for adjusting the capacity step-by-step, and means operative only after the completion of any step for adjusting the capacity by small degrees in comparison with said steps, said last named means being arranged to transmit motion to said first named means.

In testimony whereof, I have hereunto subscribed my name this 18th day of May, 1926.

VERNON I). LANDON. 

